GSE: LS1 (9-11)-2 (a) Students demonstrate an understanding of the molecular basis for heredity by- describing the DNA structure and relating the DNA sequence to the genetic code.
National Standards:
NSES:Life Sciences, content standard C, The Molecular Basis of Heredity: In all organisms, the instructions for specifying the characteristics of the organism are carried in DNA, a large polymer formed from subunits of four kinds (A, G, C, and T). The chemical and structural properties of DNA explain how the genetic information that underlies heredity is both encoded in genes (as a string of molecular "letters") and replicated by a templating mechanism. Each DNA molecule in a cell forms a single chromosome.
Context of Lesson:
Beforehand, students learn about mitosis, how cells divide. The previous lesson was meant as a review, as it is essential that students understand the overall concept and mechanism of cell division before learning about DNA structure, the more involved portions of genetics, such as inheritance, mutations, sequencing, and genetic engineering.
At this point, the students will be drawing the different molecules of DNA upon the board to build a drawn example upon the board. Next, students will be taking the different pieces that they have been given and putting the pieces of the "puzzle" together. Lesson adapted from: A Paper Model of DNA Structure & Replication, Linda A. Sigismondi, The American Biology Teacher, Vol. 51, No. 7 (Oct., 1989), pp. 422-423.
Opportunities to Learn:
Depth of Knowledge:
level 1 (recall/reproduction)
- recall the steps of mitosis when asked to draw the steps upon the board, in creating a graphic representation of the cells on the board
level 2 (Skills and Concepts):
- use a diagram of DNA to construct their own "molecule", working together to put the individual pieces together
Prerequisite Knowledge:
- Students need to have a basic knowledge of mitosis to start the class off, due to initial questioning and asking them to draw the stages upon the board.
Plans for Differentiating Instruction:
Learners who are more inclined to be:
Visual- can see the molecule upon the board, and draw it out upon their worksheet
Kinesthetic- can set up the 'puzzle pieces' of the molecule, take notes of dialog
Auditory- listen to the questions and dialog What will you do to challenge your strong learners, support your struggling learners?
Accommodations and modification
(specifics not known yet)
Molecules for puzzle can be made into simpler shapes, without the structures visible for example, and cut so that the pieces fit specifically like a puzzle
Environmental factors
Materials:
- Paper printouts (correct proportions for each class! In a set, there is one base of each kind,(4 students) four sugars 3' and 5'(one student), and four phosphates(one student)- use paperclips to hold the larger stacks together- six students in all.
- Printout of entiremolecule, to be handed out at the beginning of class for note-purposes
- glue
- posters (in multiples for correct proportion of sugars, nucleotides and phosphates)
PREP: draw and make copies of the below:
---Sugars: draw blue x and red o for 5' and 3' on back of one sheet,
---phosphates: draw blue o on back
---Adenine: draw A
---Guanine: draw G
---Thymine: draw T
---Cytosine: draw C
- chalk for chalkboard
Objectives:
Students will be able to describe the structure of DNA (sugar-phosphate backbone, nucleotide bases) by creating a puzzle-poster of the sugar-phosphate backbone and piecing the parts of the DNA structure(in paper) together.
Instruction:
Opening:
Take enough copied sheets of paper an equal amount of pieces for the class (see above preps)
Hand them a sheet with each molecular part of DNA on it, (and ask them to hold onto it until they're asked to come up and draw it)
Review of Mitosis from previous day- ask a number of students to draw a the different stages of mitosis up on the board- including chromosomes, kinetochore, microtubules, nuclear membrane Good. I'm glad you're reinforcing the previous day's work.
Next, ask different students to explain what they drew upon the board, or just pose questions to the class about it. (what are these? what do they do?)
Why not use bullets and sub-bullets for this type of dialog? Do you explain at some point why mitosis doesn't work for sexual reproduction?
Engagement:
This dialog is hard to follow.
Ask:
- "What are these things?” (point to chromosomes drawn on the board)
Ask what they do/are- explain what chromosomes are if necessary, clarify misconceptions
- “Chromosomes are: coils of DNA."
Draw DNA double helix upon the board
- "Why do you think it is important that chromosomes form coils when dividing, when DNA is normally just around the nucleus?”
- “How do we get from one cell to two? (referring to mitois) we would have to replicate everything, right?
- student response: [right.]
Explain/Lecture:
- "This is including, DNA- so the cell makes it into chromosomes! But first, we need to understand the structure of DNA before we can learn about how to replicate it." Will you eventually show an animation of this process?
- [why?] Start handing out DNA sheets with entire molecule upon it as you're speaking!
- "Lets say for example, you wanted to build a school exactly like this one. We would need to learn all about the structure first, before we could continue building it, you would need to understand the different parts -all of the plumbing and electrical work and ventilation- before attempting to start working the walls”
- "Today, we are not going to build another school, we are going to "build" a DNA molecule!" I like your use of analogies. Be sure each analogy doesn't communicate some sort of misconception.
- "What you have in your hands, are pieces of DNA molecules. DNA is made up of a "sugar-phosphate backbone" and four nucleotide bases, (Adenine, thymine, guanine, cytosine).
- "who has the paper with a red 'x' on the back?" and the blue 'o' on the top?)"
clarify that there will be two people with 'x' and 'o'.
- Ask the students to start drawing theirs upon the board, and leave spaces between each molecule (between two, and in the center between them!)
EXPLAIN:
- "student 1 and student 2 (use their NAMES!) are starting to draw the sugar-phosphate backbone! They are the "sugar" components of the backbone, so we've gotten the sugar part. Half of the backbone."
- "Next, lets finish this backbone! Who thinks that they have the phosphates? The ones with phosphorus?"(if its not that far: "or the ones with the blue 'o'.")
- "Okay, you too, come draw yours too, right beneath the sugar", and on the other side, between the spaces of the sugars" "LOOK! We've got the first part of a DNA molecule! The backbone!"
Explain/ask what a normal backbone does: supports an organism's structure- so does this one!
- depending on the class, ask for a student to come and stand in front of the class, and ask them to turn around so that we can see their backbone- ask them to bend from side to side!
- "Lets start putting the guts back together with this nucleic acid! So who has the "A"? its your turn, come and draw it!" What is she/he drawing? They're starting to draw the nucleotide sequence! You have what’s called "adenine"
- Nucleotide bases come in different shapes, called purines and pyrimidines, these fit together just like a puzzle. Who has a molecule that with a T on the back?"
-Here, you have what is called thymine. Can you draw it right here-next to the adenine?”
-“Here, look at the shapes of these molecules.”
- “Who has not gone yet?” “the G and C?”
- “Here, G, draw yours here, and C, draw yours right next to it.”
- “Now, nucleotides are made of two different types of molecules, purines and pyrimidines. Each one of these molecules pairs up with the other of its complement.
Write on board- PURINE+PYRIMIDINE
-“Like peanut butter and jelly! Very different, but they work together. It wouldn’t work if it were just peanut butter and peanut butter, or jelly and jelly. You can’t make pb&j with only ‘pb’ or just ‘j’. ”
-“Now, it is critical to remember that only certain molecules go together- ONLY A goes with T and ONLY G goes with C, since the molecules are built so that they fit together, just like a puzzle.”
--- - “Okay, now that you’ve seen how the pieces fit together, I would like you to make your own puzzle-molecule! Everyone has been given a molecule or two- look up at the board to see what you have, and write it on your sheet, at the bottom.’
- “ You’re going to find the right other molecules, and make a molecule of your own- just like a puzzle! There should be enough single molecules around to make two entire pieces of DNA, just like the one on the board”
write on board
1. Write name of your molecule on the bottom.
2. Piece molecules together, and glue on the poster paper
- “I recommend that to start, the people with sugars and phosphates get together, and the A finds a T, and the Gs find their Cs, and then find a sugar-phosphate group.”
- “Once you’re in your groups, glue the pieces together in the right order on one of the posters.”
Let students go, and piece together the molecules, walk around and clarify as needed.
Closure:
- “Bring a representative for each poster up to the front, and have them stick their two chunks of DNA together!”
- “Okay, now who can tell me about this molecule- where is the sugar-phosphate backbone?”
[murmurs, student answers]
- “Alright, now these are nucleotides, correct?”
- [yes!]
- “Now for a hard question- which ones are purines and which ones are pyrimidines?”
[purines=adenine, guanine. pyrimidines=thymine, cytosine; if they don’t catch on to it]
In this lesson, you seem to be working very hard. What are your students doing? What will the students in the back row be doing during this discussion?
The answers you anticipate your student providing are often single words or murmurs. What are you going to do to assess their understandings? How will you make your expectations for their responses clear beforehand?
Homework:
1.Remind them that their mitosis coloring sheets are due next class!
2. Ask them to find a fruit to bring into class for next period, since we're going to be extracting the DNA from their fruit! *Place emphasis upon picking fruit that they think may have LOTS of cells with nuclei, ask them to be creative about it!
Assessment:
- Students will be assessed, though not formally, upon how well they can remember mitosis and draw it upon the board
- Students can be assessed through the teacher watching how they piece the different molecules together upon the pages, and through answering the questions asked throughout the lesson
- Participation in the activity will also be taken into account as well
Lesson Plan
Lesson Title: DNA structure
State Standards:
GSE: LS1 (9-11)-2 (a) Students demonstrate an understanding of the molecular basis for heredity by- describing the DNA structure and relating the DNA sequence to the genetic code.National Standards:
NSES: Life Sciences, content standard C, The Molecular Basis of Heredity: In all organisms, the instructions for specifying the characteristics of the organism are carried in DNA, a large polymer formed from subunits of four kinds (A, G, C, and T). The chemical and structural properties of DNA explain how the genetic information that underlies heredity is both encoded in genes (as a string of molecular "letters") and replicated by a templating mechanism. Each DNA molecule in a cell forms a single chromosome.Context of Lesson:
Beforehand, students learn about mitosis, how cells divide. The previous lesson was meant as a review, as it is essential that students understand the overall concept and mechanism of cell division before learning about DNA structure, the more involved portions of genetics, such as inheritance, mutations, sequencing, and genetic engineering.At this point, the students will be drawing the different molecules of DNA upon the board to build a drawn example upon the board. Next, students will be taking the different pieces that they have been given and putting the pieces of the "puzzle" together.
Lesson adapted from: A Paper Model of DNA Structure & Replication, Linda A. Sigismondi, The American Biology Teacher, Vol. 51, No. 7 (Oct., 1989), pp. 422-423.
Opportunities to Learn:
Depth of Knowledge:
level 1 (recall/reproduction)- recall the steps of mitosis when asked to draw the steps upon the board, in creating a graphic representation of the cells on the board
level 2 (Skills and Concepts):
- use a diagram of DNA to construct their own "molecule", working together to put the individual pieces together
Prerequisite Knowledge:
- Students need to have a basic knowledge of mitosis to start the class off, due to initial questioning and asking them to draw the stages upon the board.Plans for Differentiating Instruction:
Learners who are more inclined to be:Visual- can see the molecule upon the board, and draw it out upon their worksheet
Kinesthetic- can set up the 'puzzle pieces' of the molecule, take notes of dialog
Auditory- listen to the questions and dialog
What will you do to challenge your strong learners, support your struggling learners?
Accommodations and modification
(specifics not known yet)Molecules for puzzle can be made into simpler shapes, without the structures visible for example, and cut so that the pieces fit specifically like a puzzle
Environmental factors
Materials:
- Paper printouts (correct proportions for each class! In a set, there is one base of each kind,(4 students) four sugars 3' and 5'(one student), and four phosphates(one student)- use paperclips to hold the larger stacks together- six students in all.- Printout of entiremolecule, to be handed out at the beginning of class for note-purposes
- glue
- posters (in multiples for correct proportion of sugars, nucleotides and phosphates)
PREP: draw and make copies of the below:
---Sugars: draw blue x and red o for 5' and 3' on back of one sheet
---phosphates: draw blue o on back
---Adenine: draw A
---Guanine: draw G
---Thymine: draw T
---Cytosine: draw C
- chalk for chalkboard
Objectives:
Students will be able to describe the structure of DNA (sugar-phosphate backbone, nucleotide bases) by creating a puzzle-poster of the sugar-phosphate backbone and piecing the parts of the DNA structure(in paper) together.Instruction:
Opening:
Take enough copied sheets of paper an equal amount of pieces for the class (see above preps)
Hand them a sheet with each molecular part of DNA on it, (and ask them to hold onto it until they're asked to come up and draw it)
Review of Mitosis from previous day- ask a number of students to draw a the different stages of mitosis up on the board- including chromosomes, kinetochore, microtubules, nuclear membrane Good. I'm glad you're reinforcing the previous day's work.
[ interphase- prophase- metaphase- anaphase- telophase]
Next, ask different students to explain what they drew upon the board, or just pose questions to the class about it. (what are these? what do they do?)
Why not use bullets and sub-bullets for this type of dialog? Do you explain at some point why mitosis doesn't work for sexual reproduction?
Engagement:
This dialog is hard to follow.
Ask:
- "What are these things?” (point to chromosomes drawn on the board)
Ask what they do/are- explain what chromosomes are if necessary, clarify misconceptions
- “Chromosomes are: coils of DNA."
Draw DNA double helix upon the board- "Why do you think it is important that chromosomes form coils when dividing, when DNA is normally just around the nucleus?”
- “How do we get from one cell to two? (referring to mitois) we would have to replicate everything, right?
- student response: [right.]
Explain/Lecture:
- "This is including, DNA- so the cell makes it into chromosomes! But first, we need to understand the structure of DNA before we can learn about how to replicate it." Will you eventually show an animation of this process?
- [why?] Start handing out DNA sheets with entire molecule upon it as you're speaking!
- "Lets say for example, you wanted to build a school exactly like this one. We would need to learn all about the structure first, before we could continue building it, you would need to understand the different parts -all of the plumbing and electrical work and ventilation- before attempting to start working the walls”
- "Today, we are not going to build another school, we are going to "build" a DNA molecule!" I like your use of analogies. Be sure each analogy doesn't communicate some sort of misconception.
- "What you have in your hands, are pieces of DNA molecules. DNA is made up of a "sugar-phosphate backbone" and four nucleotide bases, (Adenine, thymine, guanine, cytosine).
- "who has the paper with a red 'x' on the back?" and the blue 'o' on the top?)"
clarify that there will be two people with 'x' and 'o'.
- Ask the students to start drawing theirs upon the board, and leave spaces between each molecule (between two, and in the center between them!)
EXPLAIN:
- "student 1 and student 2 (use their NAMES!) are starting to draw the sugar-phosphate backbone! They are the "sugar" components of the backbone, so we've gotten the sugar part. Half of the backbone."
- "Next, lets finish this backbone! Who thinks that they have the phosphates? The ones with phosphorus?"(if its not that far: "or the ones with the blue 'o'.")
- "Okay, you too, come draw yours too, right beneath the sugar", and on the other side, between the spaces of the sugars" "LOOK! We've got the first part of a DNA molecule! The backbone!"
Explain/ask what a normal backbone does: supports an organism's structure- so does this one!
- depending on the class, ask for a student to come and stand in front of the class, and ask them to turn around so that we can see their backbone- ask them to bend from side to side!
- "Lets start putting the guts back together with this nucleic acid! So who has the "A"? its your turn, come and draw it!" What is she/he drawing? They're starting to draw the nucleotide sequence! You have what’s called "adenine"
- Nucleotide bases come in different shapes, called purines and pyrimidines, these fit together just like a puzzle. Who has a molecule that with a T on the back?"
-Here, you have what is called thymine. Can you draw it right here-next to the adenine?”
-“Here, look at the shapes of these molecules.”
- “Who has not gone yet?” “the G and C?”
- “Here, G, draw yours here, and C, draw yours right next to it.”
- “Now, nucleotides are made of two different types of molecules, purines and pyrimidines. Each one of these molecules pairs up with the other of its complement.
Write on board- PURINE+PYRIMIDINE
-“Like peanut butter and jelly! Very different, but they work together. It wouldn’t work if it were just peanut butter and peanut butter, or jelly and jelly. You can’t make pb&j with only ‘pb’ or just ‘j’. ”
-“Now, it is critical to remember that only certain molecules go together- ONLY A goes with T and ONLY G goes with C, since the molecules are built so that they fit together, just like a puzzle.”
--- - “Okay, now that you’ve seen how the pieces fit together, I would like you to make your own puzzle-molecule! Everyone has been given a molecule or two- look up at the board to see what you have, and write it on your sheet, at the bottom.’
- “ You’re going to find the right other molecules, and make a molecule of your own- just like a puzzle! There should be enough single molecules around to make two entire pieces of DNA, just like the one on the board”
write on board
1. Write name of your molecule on the bottom.
2. Piece molecules together, and glue on the poster paper
- “I recommend that to start, the people with sugars and phosphates get together, and the A finds a T, and the Gs find their Cs, and then find a sugar-phosphate group.”
- “Once you’re in your groups, glue the pieces together in the right order on one of the posters.”
Let students go, and piece together the molecules, walk around and clarify as needed.
Closure:
- “Bring a representative for each poster up to the front, and have them stick their two chunks of DNA together!”
- “Okay, now who can tell me about this molecule- where is the sugar-phosphate backbone?”
[murmurs, student answers]
- “Alright, now these are nucleotides, correct?”
- [yes!]
- “Now for a hard question- which ones are purines and which ones are pyrimidines?”
[purines=adenine, guanine. pyrimidines=thymine, cytosine; if they don’t catch on to it]
In this lesson, you seem to be working very hard. What are your students doing? What will the students in the back row be doing during this discussion?
The answers you anticipate your student providing are often single words or murmurs. What are you going to do to assess their understandings? How will you make your expectations for their responses clear beforehand?
Homework:
1.Remind them that their mitosis coloring sheets are due next class!
2. Ask them to find a fruit to bring into class for next period, since we're going to be extracting the DNA from their fruit! *Place emphasis upon picking fruit that they think may have LOTS of cells with nuclei, ask them to be creative about it!
Assessment:
- Students will be assessed, though not formally, upon how well they can remember mitosis and draw it upon the board- Students can be assessed through the teacher watching how they piece the different molecules together upon the pages, and through answering the questions asked throughout the lesson
- Participation in the activity will also be taken into account as well
Reflections
(only done after lesson is enacted)
Student Work Sample 1 – Approaching Proficiency:
Student Work Sample 2 – Proficient:
Student Work Sample 3 – Exceeds Proficiency: